Vibronic quantum dynamics of ultralong-range high-$\ell$ Rydberg molecules

TL;DR

This paper studies the quantum dynamics of ultralong-range Rydberg molecules, revealing how vibronic coupling influences their stability, decay pathways, and dynamical behaviors like tunneling, with results dependent on the principal quantum number.

Contribution

It introduces a vibronic two-channel model for high-$\ell$ Rydberg molecules, showing non-adiabatic stabilization and complex tunneling effects influenced by electronic structure and quantum number.

Findings

Vibronic coupling varies with principal quantum number n.

Non-adiabatic stabilization can extend molecular lifetimes.

Multi-well tunneling effects observed during low-energy oscillations.

Abstract

We investigate the non-adiabatic quantum dynamics of ultralong-range Rydberg molecules using a vibronically coupled two-channel treatment. The two channels are composed of coupled trilobite and butterfly electronic states, formed as a result of $S$-wave and $P$-wave scattering of high angular momentum Rydberg electrons with perturbing ground state atoms. Within the Born-Oppenheimer treatment, the $P$-wave scattering channel introduces an adiabatic decay pathway that affects the stability and lifetimes of trilobite states. Our numerical results show that the vibronic coupling is dependent on the principal quantum number $n$, and for certain $n$ there is non-adiabatic stabilization against internal molecular decay, facilitating previously studied dynamical effects in pure trilobite molecules. Apart from the internal diffraction effect we also observe interesting multi-well tunneling effects, during low-energy oscillations for certain $n$-values. Our work serves to highlight that the unique $R$-dependent electronic structure of these polar molecules, along with high level densities, promise many exciting dynamical effects.